Manning's fomula

By using of Penman formula, the authors calculated the evapotranspiration since 1980s, and analyzed the variation tendency of some climatic factors such as evapotranspiration, sunshine duration, air temperature, air saturation deficit etc, and focused on their impact to the evapotranspiration.

利用彭曼公式计算了 80年代以来黄河上游流域蒸散量 ,分析了该地区蒸散量、日照时数、气温、空气饱和差等气候因子的变化趋势 ,着重研究了诸因子对蒸散量的影响。

At the same time the dynamic and energy items of Penman formula are analyzed.

本文利用全国468个气象站1957—2001年20cm口径蒸发皿蒸发量及相应气象因子的实测资料,通过讨论彭曼公式中能量平衡项和空气动力学项及各气象因子的变化趋势,分析了我国蒸发皿蒸发量的变化及引起其变化的原因,同时分析了小型蒸发皿折算系数的时空分布特征并建立了回归方程。

The outcomes show that a) to use Manning formula to calculate the bankfull discharge of such major bed of the lower Yellow River will have a big deviation;b) it considers that relative stage-discharge curve,which reflects section and absolute elevation not affecting the curve is changed gradually;.

结论认为:①用曼宁公式等方法计算诸如黄河下游河道这样的河流大断面的平滩流量会带来很大的偏差;②用相对水位流量关系来反映断面与绝对高程无关的水位流量关系,认为相对水位流量关系沿程是逐渐变化的;③提出了在汛期利用经过分析取舍后的出水高度资料计算平滩流量的实时校正的方法,但这种方法计算的平滩流量多数情况下偏于保守;④新方法的计算结果很大程度上依赖于观测资料的精度和可靠性,因此,在利用实测资料之前需要对其进行具体分析。

Manning formula is often chosen to determine ti.

河流的非稳定流解析中经常采用曼宁公式来计算阻力项，但对宽浅型河流直接用曼宁公式将得出不合理的结果。

To calculate self and mutual inductance of coreless transformer in printed circuit board, The author offered a new method to calculate based on Neumann equation as well as testing process and circuit.

为了计算印制版空芯变压器的自感和互感,提出一个以纽曼公式为基础的新的计算方法,并给出了测试方法和测试电路。